1. Field of the Invention
This invention relates to computer security, and more particularly to the use of a proximity detector to continuously authorize a computer for use only by authorized persons.
2. Background of Related Art
There are many purposes for securing a computer against unauthorized use. For instance, the computer may provide access to accounting records or other sensitive information, particularly when the computer is located in an area accessible by many persons, e.g., as in a large office.
A well known and by far the most prevalent technique for preventing unauthorized access to a computer is by entering a unique password as depicted in FIG. 8. In FIG. 8, an authorized user boots up or otherwise starts a computer 130, perhaps at the beginning of their day. Usually, the computer contains a number of software programs, including an operating system and one or more application programs. Moreover, it is not unusual for the user to be prompted to enter two, three or even more different passwords by the various software programs (e.g., by the operating system, to access a network, and to load a particular application program) before the computer is up and running. A visual prompt for entry of each password is typically printed on the display 112 of the computer 130, which the user subsequently types on the keyboard 110 to gain authorized access for proceeding. While providing some level of security, this process typically requires a significant amount of user input and time before the computer is up and running.
During the business day, the user of the secure computer 130 may have the need to leave the room containing the computer, e.g., to go to the restroom, lunch, etc. However, as long as the computer 130 remains powered up, it will provide access to any user.
To prevent unauthorized access to the computer 130 when the authorized user(s) is (are) out of the room, the most traditional methods require the computer 130 to be turned off. However, this method is rather inconvenient because it causes significant delays in restarting the computer and re-entering the authorizing passwords when the authorized user returns. Moreover, the user may inadvertently forget to turn the computer 130 off when out of the room, leaving the computer susceptible to unauthorized use. Or, worse yet, the user may deliberately leave the computer on for quick absences from the room to eliminate the necessary down time while awaiting rebooting of the computer upon return, perhaps to increase their personal productivity.
An authorizing keyed lock 132 has been added to the external casing of many newer personal computers 130 as shown in FIG. 8. In the unlocked position, there is no change to the ordinary operation of a computer 130. However, when the authorizing keyed lock 132 is turned to the lock position, keyboard entry is prevented.
The authorizing keyed lock 132 is used most often for computers operating as servers or other multi-user tasks, and for computers which are otherwise intentionally not always attended during their operation. However, even when locked out from keyboard entry with the authorizing keyed lock 132 in the lock position, the conventional computer 130 continues to operate as previously authorized and often continues to display information on display 112. The keyed lock usually prevents new keyboard entry--it does not disable previous keyboard entries. Moreover, even an authorizing keyed lock 132 cannot prevent a computer 130 from unauthorized use when the absent user forgets to lock the computer 130 before leaving the room.
There is thus a need for a computer having an authorizing feature which is flexible enough to prevent access when the user steps out of the room even for just a minute, which is automatic without requiring instruction from the authorized user to initiate some security procedure (e.g., powering down) before an absence from the room.